/***
 * ASM: a very small and fast Java bytecode manipulation framework
 * Copyright (c) 2000-2005 INRIA, France Telecom
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the copyright holders nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */
package clojure.asm.commons;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

import clojure.asm.ClassVisitor;
import clojure.asm.Label;
import clojure.asm.MethodVisitor;
import clojure.asm.Opcodes;
import clojure.asm.Type;

/**
 * A {@link clojure.asm.MethodAdapter} with convenient methods to generate
 * code. For example, using this adapter, the class below
 * <p/>
 * <pre>
 * public class Example {
 *     public static void main(String[] args) {
 *         System.out.println(&quot;Hello world!&quot;);
 *     }
 * }
 * </pre>
 * <p/>
 * can be generated as follows:
 * <p/>
 * <pre>
 * ClassWriter cw = new ClassWriter(true);
 * cw.visit(V1_1, ACC_PUBLIC, &quot;Example&quot;, null, &quot;java/lang/Object&quot;, null);
 * <p/>
 * Method m = Method.getMethod(&quot;void &lt;init&gt; ()&quot;);
 * GeneratorAdapter mg = new GeneratorAdapter(ACC_PUBLIC, m, null, null, cw);
 * mg.loadThis();
 * mg.invokeConstructor(Type.getType(Object.class), m);
 * mg.returnValue();
 * mg.endMethod();
 * <p/>
 * m = Method.getMethod(&quot;void main (String[])&quot;);
 * mg = new GeneratorAdapter(ACC_PUBLIC + ACC_STATIC, m, null, null, cw);
 * mg.getStatic(Type.getType(System.class), &quot;out&quot;, Type.getType(PrintStream.class));
 * mg.push(&quot;Hello world!&quot;);
 * mg.invokeVirtual(Type.getType(PrintStream.class), Method.getMethod(&quot;void println (String)&quot;));
 * mg.returnValue();
 * mg.endMethod();
 * <p/>
 * cw.visitEnd();
 * </pre>
 *
 * @author Juozas Baliuka
 * @author Chris Nokleberg
 * @author Eric Bruneton
 */
public class GeneratorAdapter extends LocalVariablesSorter{

private final static Type BYTE_TYPE = Type.getObjectType("java/lang/Byte");

private final static Type BOOLEAN_TYPE = Type.getObjectType("java/lang/Boolean");

private final static Type SHORT_TYPE = Type.getObjectType("java/lang/Short");

private final static Type CHARACTER_TYPE = Type.getObjectType("java/lang/Character");

private final static Type INTEGER_TYPE = Type.getObjectType("java/lang/Integer");

private final static Type FLOAT_TYPE = Type.getObjectType("java/lang/Float");

private final static Type LONG_TYPE = Type.getObjectType("java/lang/Long");

private final static Type DOUBLE_TYPE = Type.getObjectType("java/lang/Double");

private final static Type NUMBER_TYPE = Type.getObjectType("java/lang/Number");

private final static Type OBJECT_TYPE = Type.getObjectType("java/lang/Object");

private final static Method BOOLEAN_VALUE = Method.getMethod("boolean booleanValue()");

private final static Method CHAR_VALUE = Method.getMethod("char charValue()");

private final static Method INT_VALUE = Method.getMethod("int intValue()");

private final static Method FLOAT_VALUE = Method.getMethod("float floatValue()");

private final static Method LONG_VALUE = Method.getMethod("long longValue()");

private final static Method DOUBLE_VALUE = Method.getMethod("double doubleValue()");

/**
 * Constant for the {@link #math math} method.
 */
public final static int ADD = Opcodes.IADD;

/**
 * Constant for the {@link #math math} method.
 */
public final static int SUB = Opcodes.ISUB;

/**
 * Constant for the {@link #math math} method.
 */
public final static int MUL = Opcodes.IMUL;

/**
 * Constant for the {@link #math math} method.
 */
public final static int DIV = Opcodes.IDIV;

/**
 * Constant for the {@link #math math} method.
 */
public final static int REM = Opcodes.IREM;

/**
 * Constant for the {@link #math math} method.
 */
public final static int NEG = Opcodes.INEG;

/**
 * Constant for the {@link #math math} method.
 */
public final static int SHL = Opcodes.ISHL;

/**
 * Constant for the {@link #math math} method.
 */
public final static int SHR = Opcodes.ISHR;

/**
 * Constant for the {@link #math math} method.
 */
public final static int USHR = Opcodes.IUSHR;

/**
 * Constant for the {@link #math math} method.
 */
public final static int AND = Opcodes.IAND;

/**
 * Constant for the {@link #math math} method.
 */
public final static int OR = Opcodes.IOR;

/**
 * Constant for the {@link #math math} method.
 */
public final static int XOR = Opcodes.IXOR;

/**
 * Constant for the {@link #ifCmp ifCmp} method.
 */
public final static int EQ = Opcodes.IFEQ;

/**
 * Constant for the {@link #ifCmp ifCmp} method.
 */
public final static int NE = Opcodes.IFNE;

/**
 * Constant for the {@link #ifCmp ifCmp} method.
 */
public final static int LT = Opcodes.IFLT;

/**
 * Constant for the {@link #ifCmp ifCmp} method.
 */
public final static int GE = Opcodes.IFGE;

/**
 * Constant for the {@link #ifCmp ifCmp} method.
 */
public final static int GT = Opcodes.IFGT;

/**
 * Constant for the {@link #ifCmp ifCmp} method.
 */
public final static int LE = Opcodes.IFLE;

/**
 * Access flags of the method visited by this adapter.
 */
private final int access;

/**
 * Return type of the method visited by this adapter.
 */
private final Type returnType;

/**
 * Argument types of the method visited by this adapter.
 */
private final Type[] argumentTypes;

/**
 * Types of the local variables of the method visited by this adapter.
 */
private final List localTypes = new ArrayList();

/**
 * Creates a new {@link GeneratorAdapter}.
 *
 * @param mv     the method visitor to which this adapter delegates calls.
 * @param access the method's access flags (see {@link Opcodes}).
 * @param name   the method's name.
 * @param desc   the method's descriptor (see {@link Type Type}).
 */
public GeneratorAdapter(
		final MethodVisitor mv,
		final int access,
		final String name,
		final String desc){
	super(access, desc, mv);
	this.access = access;
	this.returnType = Type.getReturnType(desc);
	this.argumentTypes = Type.getArgumentTypes(desc);
}

/**
 * Creates a new {@link GeneratorAdapter}.
 *
 * @param access access flags of the adapted method.
 * @param method the adapted method.
 * @param mv     the method visitor to which this adapter delegates calls.
 */
public GeneratorAdapter(
		final int access,
		final Method method,
		final MethodVisitor mv){
	super(access, method.getDescriptor(), mv);
	this.access = access;
	this.returnType = method.getReturnType();
	this.argumentTypes = method.getArgumentTypes();
}

/**
 * Creates a new {@link GeneratorAdapter}.
 *
 * @param access     access flags of the adapted method.
 * @param method     the adapted method.
 * @param signature  the signature of the adapted method (may be
 *                   <tt>null</tt>).
 * @param exceptions the exceptions thrown by the adapted method (may be
 *                   <tt>null</tt>).
 * @param cv         the class visitor to which this adapter delegates calls.
 */
public GeneratorAdapter(
		final int access,
		final Method method,
		final String signature,
		final Type[] exceptions,
		final ClassVisitor cv){
	this(access, method, cv.visitMethod(access,
	                                    method.getName(),
	                                    method.getDescriptor(),
	                                    signature,
	                                    getInternalNames(exceptions)));
}

/**
 * Returns the internal names of the given types.
 *
 * @param types a set of types.
 * @return the internal names of the given types.
 */
private static String[] getInternalNames(final Type[] types){
	if(types == null)
		{
		return null;
		}
	String[] names = new String[types.length];
	for(int i = 0; i < names.length; ++i)
		{
		names[i] = types[i].getInternalName();
		}
	return names;
}

// ------------------------------------------------------------------------
// Instructions to push constants on the stack
// ------------------------------------------------------------------------

/**
 * Generates the instruction to push the given value on the stack.
 *
 * @param value the value to be pushed on the stack.
 */
public void push(final boolean value){
	push(value ? 1 : 0);
}

/**
 * Generates the instruction to push the given value on the stack.
 *
 * @param value the value to be pushed on the stack.
 */
public void push(final int value){
	if(value >= -1 && value <= 5)
		{
		mv.visitInsn(Opcodes.ICONST_0 + value);
		}
	else if(value >= Byte.MIN_VALUE && value <= Byte.MAX_VALUE)
		{
		mv.visitIntInsn(Opcodes.BIPUSH, value);
		}
	else if(value >= Short.MIN_VALUE && value <= Short.MAX_VALUE)
		{
		mv.visitIntInsn(Opcodes.SIPUSH, value);
		}
	else
		{
		mv.visitLdcInsn(new Integer(value));
		}
}

/**
 * Generates the instruction to push the given value on the stack.
 *
 * @param value the value to be pushed on the stack.
 */
public void push(final long value){
	if(value == 0L || value == 1L)
		{
		mv.visitInsn(Opcodes.LCONST_0 + (int) value);
		}
	else
		{
		mv.visitLdcInsn(new Long(value));
		}
}

/**
 * Generates the instruction to push the given value on the stack.
 *
 * @param value the value to be pushed on the stack.
 */
public void push(final float value){
	int bits = Float.floatToIntBits(value);
	if(bits == 0L || bits == 0x3f800000 || bits == 0x40000000)
		{ // 0..2
		mv.visitInsn(Opcodes.FCONST_0 + (int) value);
		}
	else
		{
		mv.visitLdcInsn(new Float(value));
		}
}

/**
 * Generates the instruction to push the given value on the stack.
 *
 * @param value the value to be pushed on the stack.
 */
public void push(final double value){
	long bits = Double.doubleToLongBits(value);
	if(bits == 0L || bits == 0x3ff0000000000000L)
		{ // +0.0d and 1.0d
		mv.visitInsn(Opcodes.DCONST_0 + (int) value);
		}
	else
		{
		mv.visitLdcInsn(new Double(value));
		}
}

/**
 * Generates the instruction to push the given value on the stack.
 *
 * @param value the value to be pushed on the stack. May be <tt>null</tt>.
 */
public void push(final String value){
	if(value == null)
		{
		mv.visitInsn(Opcodes.ACONST_NULL);
		}
	else
		{
		mv.visitLdcInsn(value);
		}
}

/**
 * Generates the instruction to push the given value on the stack.
 *
 * @param value the value to be pushed on the stack.
 */
public void push(final Type value){
	if(value == null)
		{
		mv.visitInsn(Opcodes.ACONST_NULL);
		}
	else
		{
		mv.visitLdcInsn(value);
		}
}

// ------------------------------------------------------------------------
// Instructions to load and store method arguments
// ------------------------------------------------------------------------

/**
 * Returns the index of the given method argument in the frame's local
 * variables array.
 *
 * @param arg the index of a method argument.
 * @return the index of the given method argument in the frame's local
 *         variables array.
 */
private int getArgIndex(final int arg){
	int index = (access & Opcodes.ACC_STATIC) == 0 ? 1 : 0;
	for(int i = 0; i < arg; i++)
		{
		index += argumentTypes[i].getSize();
		}
	return index;
}

/**
 * Generates the instruction to push a local variable on the stack.
 *
 * @param type  the type of the local variable to be loaded.
 * @param index an index in the frame's local variables array.
 */
private void loadInsn(final Type type, final int index){
	mv.visitVarInsn(type.getOpcode(Opcodes.ILOAD), index);
}

/**
 * Generates the instruction to store the top stack value in a local
 * variable.
 *
 * @param type  the type of the local variable to be stored.
 * @param index an index in the frame's local variables array.
 */
private void storeInsn(final Type type, final int index){
	mv.visitVarInsn(type.getOpcode(Opcodes.ISTORE), index);
}

/**
 * Generates the instruction to load 'this' on the stack.
 */
public void loadThis(){
	if((access & Opcodes.ACC_STATIC) != 0)
		{
		throw new IllegalStateException("no 'this' pointer within static method");
		}
	mv.visitVarInsn(Opcodes.ALOAD, 0);
}

/**
 * Generates the instruction to load the given method argument on the stack.
 *
 * @param arg the index of a method argument.
 */
public void loadArg(final int arg){
	loadInsn(argumentTypes[arg], getArgIndex(arg));
}

/**
 * Generates the instructions to load the given method arguments on the
 * stack.
 *
 * @param arg   the index of the first method argument to be loaded.
 * @param count the number of method arguments to be loaded.
 */
public void loadArgs(final int arg, final int count){
	int index = getArgIndex(arg);
	for(int i = 0; i < count; ++i)
		{
		Type t = argumentTypes[arg + i];
		loadInsn(t, index);
		index += t.getSize();
		}
}

/**
 * Generates the instructions to load all the method arguments on the stack.
 */
public void loadArgs(){
	loadArgs(0, argumentTypes.length);
}

/**
 * Generates the instructions to load all the method arguments on the stack,
 * as a single object array.
 */
public void loadArgArray(){
	push(argumentTypes.length);
	newArray(OBJECT_TYPE);
	for(int i = 0; i < argumentTypes.length; i++)
		{
		dup();
		push(i);
		loadArg(i);
		box(argumentTypes[i]);
		arrayStore(OBJECT_TYPE);
		}
}

/**
 * Generates the instruction to store the top stack value in the given
 * method argument.
 *
 * @param arg the index of a method argument.
 */
public void storeArg(final int arg){
	storeInsn(argumentTypes[arg], getArgIndex(arg));
}

// ------------------------------------------------------------------------
// Instructions to load and store local variables
// ------------------------------------------------------------------------

/**
 * Returns the type of the given local variable.
 *
 * @param local a local variable identifier, as returned by
 *              {@link LocalVariablesSorter#newLocal(Type) newLocal()}.
 * @return the type of the given local variable.
 */
public Type getLocalType(final int local){
	return (Type) localTypes.get(local - firstLocal);
}

protected void setLocalType(final int local, final Type type){
	int index = local - firstLocal;
	while(localTypes.size() < index + 1)
		{
		localTypes.add(null);
		}
	localTypes.set(index, type);
}

/**
 * Generates the instruction to load the given local variable on the stack.
 *
 * @param local a local variable identifier, as returned by
 *              {@link LocalVariablesSorter#newLocal(Type) newLocal()}.
 */
public void loadLocal(final int local){
	loadInsn(getLocalType(local), local);
}

/**
 * Generates the instruction to load the given local variable on the stack.
 *
 * @param local a local variable identifier, as returned by
 *              {@link LocalVariablesSorter#newLocal(Type) newLocal()}.
 * @param type  the type of this local variable.
 */
public void loadLocal(final int local, final Type type){
	setLocalType(local, type);
	loadInsn(type, local);
}

/**
 * Generates the instruction to store the top stack value in the given local
 * variable.
 *
 * @param local a local variable identifier, as returned by
 *              {@link LocalVariablesSorter#newLocal(Type) newLocal()}.
 */
public void storeLocal(final int local){
	storeInsn(getLocalType(local), local);
}

/**
 * Generates the instruction to store the top stack value in the given local
 * variable.
 *
 * @param local a local variable identifier, as returned by
 *              {@link LocalVariablesSorter#newLocal(Type) newLocal()}.
 * @param type  the type of this local variable.
 */
public void storeLocal(final int local, final Type type){
	setLocalType(local, type);
	storeInsn(type, local);
}

/**
 * Generates the instruction to load an element from an array.
 *
 * @param type the type of the array element to be loaded.
 */
public void arrayLoad(final Type type){
	mv.visitInsn(type.getOpcode(Opcodes.IALOAD));
}

/**
 * Generates the instruction to store an element in an array.
 *
 * @param type the type of the array element to be stored.
 */
public void arrayStore(final Type type){
	mv.visitInsn(type.getOpcode(Opcodes.IASTORE));
}

// ------------------------------------------------------------------------
// Instructions to manage the stack
// ------------------------------------------------------------------------

/**
 * Generates a POP instruction.
 */
public void pop(){
	mv.visitInsn(Opcodes.POP);
}

/**
 * Generates a POP2 instruction.
 */
public void pop2(){
	mv.visitInsn(Opcodes.POP2);
}

/**
 * Generates a DUP instruction.
 */
public void dup(){
	mv.visitInsn(Opcodes.DUP);
}

/**
 * Generates a DUP2 instruction.
 */
public void dup2(){
	mv.visitInsn(Opcodes.DUP2);
}

/**
 * Generates a DUP_X1 instruction.
 */
public void dupX1(){
	mv.visitInsn(Opcodes.DUP_X1);
}

/**
 * Generates a DUP_X2 instruction.
 */
public void dupX2(){
	mv.visitInsn(Opcodes.DUP_X2);
}

/**
 * Generates a DUP2_X1 instruction.
 */
public void dup2X1(){
	mv.visitInsn(Opcodes.DUP2_X1);
}

/**
 * Generates a DUP2_X2 instruction.
 */
public void dup2X2(){
	mv.visitInsn(Opcodes.DUP2_X2);
}

/**
 * Generates a SWAP instruction.
 */
public void swap(){
	mv.visitInsn(Opcodes.SWAP);
}

/**
 * Generates the instructions to swap the top two stack values.
 *
 * @param prev type of the top - 1 stack value.
 * @param type type of the top stack value.
 */
public void swap(final Type prev, final Type type){
	if(type.getSize() == 1)
		{
		if(prev.getSize() == 1)
			{
			swap(); // same as dupX1(), pop();
			}
		else
			{
			dupX2();
			pop();
			}
		}
	else
		{
		if(prev.getSize() == 1)
			{
			dup2X1();
			pop2();
			}
		else
			{
			dup2X2();
			pop2();
			}
		}
}

// ------------------------------------------------------------------------
// Instructions to do mathematical and logical operations
// ------------------------------------------------------------------------

/**
 * Generates the instruction to do the specified mathematical or logical
 * operation.
 *
 * @param op   a mathematical or logical operation. Must be one of ADD, SUB,
 *             MUL, DIV, REM, NEG, SHL, SHR, USHR, AND, OR, XOR.
 * @param type the type of the operand(s) for this operation.
 */
public void math(final int op, final Type type){
	mv.visitInsn(type.getOpcode(op));
}

/**
 * Generates the instructions to compute the bitwise negation of the top
 * stack value.
 */
public void not(){
	mv.visitInsn(Opcodes.ICONST_1);
	mv.visitInsn(Opcodes.IXOR);
}

/**
 * Generates the instruction to increment the given local variable.
 *
 * @param local  the local variable to be incremented.
 * @param amount the amount by which the local variable must be incremented.
 */
public void iinc(final int local, final int amount){
	mv.visitIincInsn(local, amount);
}

/**
 * Generates the instructions to cast a numerical value from one type to
 * another.
 *
 * @param from the type of the top stack value
 * @param to   the type into which this value must be cast.
 */
public void cast(final Type from, final Type to){
	if(from != to)
		{
		if(from == Type.DOUBLE_TYPE)
			{
			if(to == Type.FLOAT_TYPE)
				{
				mv.visitInsn(Opcodes.D2F);
				}
			else if(to == Type.LONG_TYPE)
				{
				mv.visitInsn(Opcodes.D2L);
				}
			else
				{
				mv.visitInsn(Opcodes.D2I);
				cast(Type.INT_TYPE, to);
				}
			}
		else if(from == Type.FLOAT_TYPE)
			{
			if(to == Type.DOUBLE_TYPE)
				{
				mv.visitInsn(Opcodes.F2D);
				}
			else if(to == Type.LONG_TYPE)
				{
				mv.visitInsn(Opcodes.F2L);
				}
			else
				{
				mv.visitInsn(Opcodes.F2I);
				cast(Type.INT_TYPE, to);
				}
			}
		else if(from == Type.LONG_TYPE)
			{
			if(to == Type.DOUBLE_TYPE)
				{
				mv.visitInsn(Opcodes.L2D);
				}
			else if(to == Type.FLOAT_TYPE)
				{
				mv.visitInsn(Opcodes.L2F);
				}
			else
				{
				mv.visitInsn(Opcodes.L2I);
				cast(Type.INT_TYPE, to);
				}
			}
		else
			{
			if(to == Type.BYTE_TYPE)
				{
				mv.visitInsn(Opcodes.I2B);
				}
			else if(to == Type.CHAR_TYPE)
				{
				mv.visitInsn(Opcodes.I2C);
				}
			else if(to == Type.DOUBLE_TYPE)
				{
				mv.visitInsn(Opcodes.I2D);
				}
			else if(to == Type.FLOAT_TYPE)
				{
				mv.visitInsn(Opcodes.I2F);
				}
			else if(to == Type.LONG_TYPE)
				{
				mv.visitInsn(Opcodes.I2L);
				}
			else if(to == Type.SHORT_TYPE)
				{
				mv.visitInsn(Opcodes.I2S);
				}
			}
		}
}

// ------------------------------------------------------------------------
// Instructions to do boxing and unboxing operations
// ------------------------------------------------------------------------

/**
 * Generates the instructions to box the top stack value. This value is
 * replaced by its boxed equivalent on top of the stack.
 *
 * @param type the type of the top stack value.
 */
public void box(final Type type){
	if(type.getSort() == Type.OBJECT || type.getSort() == Type.ARRAY)
		{
		return;
		}
	if(type == Type.VOID_TYPE)
		{
		push((String) null);
		}
	else
		{
		Type boxed = type;
		switch(type.getSort())
			{
			case Type.BYTE:
				boxed = BYTE_TYPE;
				break;
			case Type.BOOLEAN:
				boxed = BOOLEAN_TYPE;
				break;
			case Type.SHORT:
				boxed = SHORT_TYPE;
				break;
			case Type.CHAR:
				boxed = CHARACTER_TYPE;
				break;
			case Type.INT:
				boxed = INTEGER_TYPE;
				break;
			case Type.FLOAT:
				boxed = FLOAT_TYPE;
				break;
			case Type.LONG:
				boxed = LONG_TYPE;
				break;
			case Type.DOUBLE:
				boxed = DOUBLE_TYPE;
				break;
			}
		newInstance(boxed);
		if(type.getSize() == 2)
			{
			// Pp -> Ppo -> oPpo -> ooPpo -> ooPp -> o
			dupX2();
			dupX2();
			pop();
			}
		else
			{
			// p -> po -> opo -> oop -> o
			dupX1();
			swap();
			}
		invokeConstructor(boxed, new Method("<init>",
		                                    Type.VOID_TYPE,
		                                    new Type[]{type}));
		}
}

/**
 * Generates the instructions to unbox the top stack value. This value is
 * replaced by its unboxed equivalent on top of the stack.
 *
 * @param type the type of the top stack value.
 */
public void unbox(final Type type){
	Type t = NUMBER_TYPE;
	Method sig = null;
	switch(type.getSort())
		{
		case Type.VOID:
			return;
		case Type.CHAR:
			t = CHARACTER_TYPE;
			sig = CHAR_VALUE;
			break;
		case Type.BOOLEAN:
			t = BOOLEAN_TYPE;
			sig = BOOLEAN_VALUE;
			break;
		case Type.DOUBLE:
			sig = DOUBLE_VALUE;
			break;
		case Type.FLOAT:
			sig = FLOAT_VALUE;
			break;
		case Type.LONG:
			sig = LONG_VALUE;
			break;
		case Type.INT:
		case Type.SHORT:
		case Type.BYTE:
			sig = INT_VALUE;
		}
	if(sig == null)
		{
		checkCast(type);
		}
	else
		{
		checkCast(t);
		invokeVirtual(t, sig);
		}
}

// ------------------------------------------------------------------------
// Instructions to jump to other instructions
// ------------------------------------------------------------------------

/**
 * Creates a new {@link Label}.
 *
 * @return a new {@link Label}.
 */
public Label newLabel(){
	return new Label();
}

/**
 * Marks the current code position with the given label.
 *
 * @param label a label.
 */
public void mark(final Label label){
	mv.visitLabel(label);
}

/**
 * Marks the current code position with a new label.
 *
 * @return the label that was created to mark the current code position.
 */
public Label mark(){
	Label label = new Label();
	mv.visitLabel(label);
	return label;
}

/**
 * Generates the instructions to jump to a label based on the comparison of
 * the top two stack values.
 *
 * @param type  the type of the top two stack values.
 * @param mode  how these values must be compared. One of EQ, NE, LT, GE, GT,
 *              LE.
 * @param label where to jump if the comparison result is <tt>true</tt>.
 */
public void ifCmp(final Type type, final int mode, final Label label){
	int intOp = -1;
	switch(type.getSort())
		{
		case Type.LONG:
			mv.visitInsn(Opcodes.LCMP);
			break;
		case Type.DOUBLE:
			mv.visitInsn(Opcodes.DCMPG);
			break;
		case Type.FLOAT:
			mv.visitInsn(Opcodes.FCMPG);
			break;
		case Type.ARRAY:
		case Type.OBJECT:
			switch(mode)
				{
				case EQ:
					mv.visitJumpInsn(Opcodes.IF_ACMPEQ, label);
					return;
				case NE:
					mv.visitJumpInsn(Opcodes.IF_ACMPNE, label);
					return;
				}
			throw new IllegalArgumentException("Bad comparison for type "
			                                   + type);
		default:
			switch(mode)
				{
				case EQ:
					intOp = Opcodes.IF_ICMPEQ;
					break;
				case NE:
					intOp = Opcodes.IF_ICMPNE;
					break;
				case GE:
					intOp = Opcodes.IF_ICMPGE;
					break;
				case LT:
					intOp = Opcodes.IF_ICMPLT;
					break;
				case LE:
					intOp = Opcodes.IF_ICMPLE;
					break;
				case GT:
					intOp = Opcodes.IF_ICMPGT;
					break;
				}
			mv.visitJumpInsn(intOp, label);
			return;
		}
	int jumpMode = mode;
	switch(mode)
		{
		case GE:
			jumpMode = LT;
			break;
		case LE:
			jumpMode = GT;
			break;
		}
	mv.visitJumpInsn(jumpMode, label);
}

/**
 * Generates the instructions to jump to a label based on the comparison of
 * the top two integer stack values.
 *
 * @param mode  how these values must be compared. One of EQ, NE, LT, GE, GT,
 *              LE.
 * @param label where to jump if the comparison result is <tt>true</tt>.
 */
public void ifICmp(final int mode, final Label label){
	ifCmp(Type.INT_TYPE, mode, label);
}

/**
 * Generates the instructions to jump to a label based on the comparison of
 * the top integer stack value with zero.
 *
 * @param mode  how these values must be compared. One of EQ, NE, LT, GE, GT,
 *              LE.
 * @param label where to jump if the comparison result is <tt>true</tt>.
 */
public void ifZCmp(final int mode, final Label label){
	mv.visitJumpInsn(mode, label);
}

/**
 * Generates the instruction to jump to the given label if the top stack
 * value is null.
 *
 * @param label where to jump if the condition is <tt>true</tt>.
 */
public void ifNull(final Label label){
	mv.visitJumpInsn(Opcodes.IFNULL, label);
}

/**
 * Generates the instruction to jump to the given label if the top stack
 * value is not null.
 *
 * @param label where to jump if the condition is <tt>true</tt>.
 */
public void ifNonNull(final Label label){
	mv.visitJumpInsn(Opcodes.IFNONNULL, label);
}

/**
 * Generates the instruction to jump to the given label.
 *
 * @param label where to jump if the condition is <tt>true</tt>.
 */
public void goTo(final Label label){
	mv.visitJumpInsn(Opcodes.GOTO, label);
}

/**
 * Generates a RET instruction.
 *
 * @param local a local variable identifier, as returned by
 *              {@link LocalVariablesSorter#newLocal(Type) newLocal()}.
 */
public void ret(final int local){
	mv.visitVarInsn(Opcodes.RET, local);
}

/**
 * Generates the instructions for a switch statement.
 *
 * @param keys      the switch case keys.
 * @param generator a generator to generate the code for the switch cases.
 */
public void tableSwitch(
		final int[] keys,
		final TableSwitchGenerator generator){
	float density;
	if(keys.length == 0)
		{
		density = 0;
		}
	else
		{
		density = (float) keys.length
		          / (keys[keys.length - 1] - keys[0] + 1);
		}
	tableSwitch(keys, generator, density >= 0.5f);
}

/**
 * Generates the instructions for a switch statement.
 *
 * @param keys      the switch case keys.
 * @param generator a generator to generate the code for the switch cases.
 * @param useTable  <tt>true</tt> to use a TABLESWITCH instruction, or
 *                  <tt>false</tt> to use a LOOKUPSWITCH instruction.
 */
public void tableSwitch(
		final int[] keys,
		final TableSwitchGenerator generator,
		final boolean useTable){
	for(int i = 1; i < keys.length; ++i)
		{
		if(keys[i] < keys[i - 1])
			{
			throw new IllegalArgumentException("keys must be sorted ascending");
			}
		}
	Label def = newLabel();
	Label end = newLabel();
	if(keys.length > 0)
		{
		int len = keys.length;
		int min = keys[0];
		int max = keys[len - 1];
		int range = max - min + 1;
		if(useTable)
			{
			Label[] labels = new Label[range];
			Arrays.fill(labels, def);
			for(int i = 0; i < len; ++i)
				{
				labels[keys[i] - min] = newLabel();
				}
			mv.visitTableSwitchInsn(min, max, def, labels);
			for(int i = 0; i < range; ++i)
				{
				Label label = labels[i];
				if(label != def)
					{
					mark(label);
					generator.generateCase(i + min, end);
					}
				}
			}
		else
			{
			Label[] labels = new Label[len];
			for(int i = 0; i < len; ++i)
				{
				labels[i] = newLabel();
				}
			mv.visitLookupSwitchInsn(def, keys, labels);
			for(int i = 0; i < len; ++i)
				{
				mark(labels[i]);
				generator.generateCase(keys[i], end);
				}
			}
		}
	mark(def);
	generator.generateDefault();
	mark(end);
}

/**
 * Generates the instruction to return the top stack value to the caller.
 */
public void returnValue(){
	mv.visitInsn(returnType.getOpcode(Opcodes.IRETURN));
}

// ------------------------------------------------------------------------
// Instructions to load and store fields
// ------------------------------------------------------------------------

/**
 * Generates a get field or set field instruction.
 *
 * @param opcode    the instruction's opcode.
 * @param ownerType the class in which the field is defined.
 * @param name      the name of the field.
 * @param fieldType the type of the field.
 */
private void fieldInsn(
		final int opcode,
		final Type ownerType,
		final String name,
		final Type fieldType){
	mv.visitFieldInsn(opcode,
	                  ownerType.getInternalName(),
	                  name,
	                  fieldType.getDescriptor());
}

/**
 * Generates the instruction to push the value of a static field on the
 * stack.
 *
 * @param owner the class in which the field is defined.
 * @param name  the name of the field.
 * @param type  the type of the field.
 */
public void getStatic(final Type owner, final String name, final Type type){
	fieldInsn(Opcodes.GETSTATIC, owner, name, type);
}

/**
 * Generates the instruction to store the top stack value in a static field.
 *
 * @param owner the class in which the field is defined.
 * @param name  the name of the field.
 * @param type  the type of the field.
 */
public void putStatic(final Type owner, final String name, final Type type){
	fieldInsn(Opcodes.PUTSTATIC, owner, name, type);
}

/**
 * Generates the instruction to push the value of a non static field on the
 * stack.
 *
 * @param owner the class in which the field is defined.
 * @param name  the name of the field.
 * @param type  the type of the field.
 */
public void getField(final Type owner, final String name, final Type type){
	fieldInsn(Opcodes.GETFIELD, owner, name, type);
}

/**
 * Generates the instruction to store the top stack value in a non static
 * field.
 *
 * @param owner the class in which the field is defined.
 * @param name  the name of the field.
 * @param type  the type of the field.
 */
public void putField(final Type owner, final String name, final Type type){
	fieldInsn(Opcodes.PUTFIELD, owner, name, type);
}

// ------------------------------------------------------------------------
// Instructions to invoke methods
// ------------------------------------------------------------------------

/**
 * Generates an invoke method instruction.
 *
 * @param opcode the instruction's opcode.
 * @param type   the class in which the method is defined.
 * @param method the method to be invoked.
 */
private void invokeInsn(
		final int opcode,
		final Type type,
		final Method method){
	String owner = type.getSort() == Type.ARRAY
	               ? type.getDescriptor()
	               : type.getInternalName();
	mv.visitMethodInsn(opcode,
	                   owner,
	                   method.getName(),
	                   method.getDescriptor());
}

/**
 * Generates the instruction to invoke a normal method.
 *
 * @param owner  the class in which the method is defined.
 * @param method the method to be invoked.
 */
public void invokeVirtual(final Type owner, final Method method){
	invokeInsn(Opcodes.INVOKEVIRTUAL, owner, method);
}

/**
 * Generates the instruction to invoke a constructor.
 *
 * @param type   the class in which the constructor is defined.
 * @param method the constructor to be invoked.
 */
public void invokeConstructor(final Type type, final Method method){
	invokeInsn(Opcodes.INVOKESPECIAL, type, method);
}

/**
 * Generates the instruction to invoke a static method.
 *
 * @param owner  the class in which the method is defined.
 * @param method the method to be invoked.
 */
public void invokeStatic(final Type owner, final Method method){
	invokeInsn(Opcodes.INVOKESTATIC, owner, method);
}

/**
 * Generates the instruction to invoke an interface method.
 *
 * @param owner  the class in which the method is defined.
 * @param method the method to be invoked.
 */
public void invokeInterface(final Type owner, final Method method){
	invokeInsn(Opcodes.INVOKEINTERFACE, owner, method);
}

// ------------------------------------------------------------------------
// Instructions to create objects and arrays
// ------------------------------------------------------------------------

/**
 * Generates a type dependent instruction.
 *
 * @param opcode the instruction's opcode.
 * @param type   the instruction's operand.
 */
private void typeInsn(final int opcode, final Type type){
	String desc;
	if(type.getSort() == Type.ARRAY)
		{
		desc = type.getDescriptor();
		}
	else
		{
		desc = type.getInternalName();
		}
	mv.visitTypeInsn(opcode, desc);
}

/**
 * Generates the instruction to create a new object.
 *
 * @param type the class of the object to be created.
 */
public void newInstance(final Type type){
	typeInsn(Opcodes.NEW, type);
}

/**
 * Generates the instruction to create a new array.
 *
 * @param type the type of the array elements.
 */
public void newArray(final Type type){
	int typ;
	switch(type.getSort())
		{
		case Type.BOOLEAN:
			typ = Opcodes.T_BOOLEAN;
			break;
		case Type.CHAR:
			typ = Opcodes.T_CHAR;
			break;
		case Type.BYTE:
			typ = Opcodes.T_BYTE;
			break;
		case Type.SHORT:
			typ = Opcodes.T_SHORT;
			break;
		case Type.INT:
			typ = Opcodes.T_INT;
			break;
		case Type.FLOAT:
			typ = Opcodes.T_FLOAT;
			break;
		case Type.LONG:
			typ = Opcodes.T_LONG;
			break;
		case Type.DOUBLE:
			typ = Opcodes.T_DOUBLE;
			break;
		default:
			typeInsn(Opcodes.ANEWARRAY, type);
			return;
		}
	mv.visitIntInsn(Opcodes.NEWARRAY, typ);
}

// ------------------------------------------------------------------------
// Miscelaneous instructions
// ------------------------------------------------------------------------

/**
 * Generates the instruction to compute the length of an array.
 */
public void arrayLength(){
	mv.visitInsn(Opcodes.ARRAYLENGTH);
}

/**
 * Generates the instruction to throw an exception.
 */
public void throwException(){
	mv.visitInsn(Opcodes.ATHROW);
}

/**
 * Generates the instructions to create and throw an exception. The
 * exception class must have a constructor with a single String argument.
 *
 * @param type the class of the exception to be thrown.
 * @param msg  the detailed message of the exception.
 */
public void throwException(final Type type, final String msg){
	newInstance(type);
	dup();
	push(msg);
	invokeConstructor(type, Method.getMethod("void <init> (String)"));
	throwException();
}

/**
 * Generates the instruction to check that the top stack value is of the
 * given type.
 *
 * @param type a class or interface type.
 */
public void checkCast(final Type type){
	if(!type.equals(OBJECT_TYPE))
		{
		typeInsn(Opcodes.CHECKCAST, type);
		}
}

/**
 * Generates the instruction to test if the top stack value is of the given
 * type.
 *
 * @param type a class or interface type.
 */
public void instanceOf(final Type type){
	typeInsn(Opcodes.INSTANCEOF, type);
}

/**
 * Generates the instruction to get the monitor of the top stack value.
 */
public void monitorEnter(){
	mv.visitInsn(Opcodes.MONITORENTER);
}

/**
 * Generates the instruction to release the monitor of the top stack value.
 */
public void monitorExit(){
	mv.visitInsn(Opcodes.MONITOREXIT);
}

// ------------------------------------------------------------------------
// Non instructions
// ------------------------------------------------------------------------

/**
 * Marks the end of the visited method.
 */
public void endMethod(){
	if((access & Opcodes.ACC_ABSTRACT) == 0)
		{
		mv.visitMaxs(0, 0);
		}
	mv.visitEnd();
}

/**
 * Marks the start of an exception handler.
 *
 * @param start     beginning of the exception handler's scope (inclusive).
 * @param end       end of the exception handler's scope (exclusive).
 * @param exception internal name of the type of exceptions handled by the
 *                  handler.
 */
public void catchException(
		final Label start,
		final Label end,
		final Type exception){
	mv.visitTryCatchBlock(start, end, mark(), exception.getInternalName());
}
}
